Identification of reference housekeeping-genes for mRNA expression studies in patients with type 1 diabetes.

Selection of appropriate housekeeping-genes as reference is important in mRNA expression-related experiments. It is more important in diabetes since hyperglycemia per se can influence expression of housekeeping-genes. RNA expression of Glyceraldehyde-3-phosphate-dehydrogenase, ß-actin and 18S-ribosomal-RNA, Hypoxanthine-phosphoribosyl-transferase (HPRT), Tyrosine-3-monooxygenase/tryptophan (YHWAZ), ß2-microglobin (ß2M), TATA-binding-protein (TBP), and Ubiquitin C and cytochrome1 (CYC1) assessed in circulating-lymphocytes-(PBMC) of patients with type-1-diabetes and healthy controls. The stability ('M' value <1.02) and number of housekeeping-genes required for normalization in qRT-PCR were determined by 'ge-norm software.' Vitamin-D-receptor (VDR) was used as a target gene. All the nine genes tested had sufficient 'M' value in diabetes and healthy controls. However, housekeeping-genes indicated a relatively higher stability of expression in healthy controls in comparison to diabetes. Use of single housekeeping-genes brought gross variation in the calculation of VDR-mRNA copies. The ge-norm software suggested geometric mean of five housekeeping-genes for ideal normalization in diabetes (CYC1, ß-actin, YHWAZ, HPRT, and ß2M) and only three in controls (CYC1, ß-actin, and TBP). HbA1c did not correlate with expression of any of the nine housekeeping-genes. Thus, geometric mean of CYC1, ß-actin, YHWAZ, HPRT, and ß2M needs to be used for ideal normalization of mRNA in type-1-diabetes. Similar studies are required in other population.

Interpreting Cardiovascular Endpoints in Trials of Antihyperglycemic Drugs.

In view of the significant cardiovascular (CV) morbidity and mortality in patients with type 2 diabetes mellitus, and concerns raised about the CV safety of some glucose-lowering drugs, the US Food and Drug Administration (FDA) issued guidance for the industry in 2008 to demonstrate CV safety for the approval of all new antihyperglycemic drugs. Seven randomized controlled trials involving around 60,000 participants have been completed so far and have demonstrated the CV safety of dipeptidyl peptidase 4 inhibitors (saxagliptin, alogliptin and sitagliptin), glucagon-like peptide-1 receptor agonists (lixisenatide, liraglutide and semaglutide) and a sodium-glucose co-transporter 2 inhibitor (empagliflozin) in patients with type 2 diabetes. Three of these trials have in fact reported superiority of the study drug over placebo in terms of CV outcomes. However, all these trials were primarily designed as non-inferiority trials to exclude an unacceptable risk of CV events with these drugs in the shortest possible time period. The potential long-term benefit or risks were not assessed effectively as the median follow-up in these studies was limited to 1.5-3 years. Also, these trials included patients with relatively long duration of diabetes, advanced atherosclerosis and higher CV risk. Thus, these trials were not intended to assess CV benefit and are best interpreted as evidence for CV safety of these antihyperglycemic medications.

Vertebral Fractures and Bone Mineral Density in Patients With Idiopathic Hypoparathyroidism on Long-Term Follow-Up.

Context: Bone mineral density (BMD) is increased in idiopathic hypoparathyroidism (IH). Parathyroid hormone (PTH) deficiency, hypocalcemic seizures, and anticonvulsants could compromise skeletal health in IH. Objective: We assessed vertebral fractures (VFs) and related factors in IH and change in BMD during follow-up. Design: VFs were assessed by morphometry. BMD was assessed by dual-energy X-ray absorptiometery at the lumbar spine, hip, and forearm. Change in BMD was assessed in a subset after a 10-year follow-up. Setting: The endocrine clinic of All India Institute of Medical Sciences, New Delhi, India. Subjects: Included were 104 patients with IH and 64 healthy controls. Hypocalcemia, hyperphosphatemia, normal kidney function, and low serum PTH levels were used to diagnose IH. Results: VFs were seen in 18.3% of patients with IH and 4.7% of controls (odds ratio, 4.54; 95% confidence interval, 1.28 to 16.04). Use of anticonvulsants and menopause were significantly associated (P < 0.05) with VF. Mean BMD at lumbar spine and hip were higher by 21.4% and 8.6%, respectively, in IH than in controls (P < 0.001), respectively. BMD significantly increased during follow-up at all sites. Change in BMD correlated with maintenance of the serum calcium/phosphorus ratio during follow-up. Conclusions: Despite increased BMD, prevalence of vertebral-fractures is greater in patients with IH, especially in postmenopausal women and those on anticonvulsant therapy.

Primary hyperparathyroidism may masquerade as rickets-osteomalacia in vitamin D replete children.

Primary hyperparathyroidism, typically a disease of the middle aged and the old, is less commonly seen in children. In children the disease has a bimodal age distribution with calcium sensing receptor mutation presenting in infancy as hypercalcemic crises and parathyroid adenoma or hyperplasia presenting later in childhood with bone disease. The childhood parathyroid adenomas are often familial with multiglandular disease and manifest with severe bone disease unlike adults. We report a series of four male patients with juvenile primary hyperparathyroidism, three of whom presented with bone disease masquerading as rickets-osteomalacia. One patient had asymptomatic hypercalcemia with short stature. Parathyroid adenoma was detected in all the four cases and all of them underwent resection of parathyroid adenomas confirmed on histopathology. Post-surgery all the cases had initial hypocalcaemia followed by normocalcemia. One case developed pancreatitis after surgery even after achieving normocalcemia. We conclude that parathyroid adenomas, although uncommon in children, are an important cause of skeletal disease that may initially be confused with hypovitaminosis D.